About the Photo

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Photometers on Izaña Observatory, Tenerife

A variety of different measurements of atmospheric properties are taken at the Izaña Observatory. The three photometers in the photograph above are used for observing the characteristics of aerosol particles. Other instruments monitor atmospheric levels of heat-trapping greenhouse gases.

These measurements have been taken for more than 30 years. Over this period, atmospheric CO2 levels at Izaña have increased from roughly 345 parts per million to well over 400 parts per million. This inexorable increase is both compelling and concerning. Izaña is on Tenerife, the largest and most populous of Spain's Canary Islands. Located in the Atlantic Ocean off the northeast coast of Africa, the site is high up on a volcano (Mt. Teide) and far removed from urban pollution sources.

Measurements made at Izaña and elsewhere document how human activities are changing the chemical composition of Earth's atmosphere, even in some of the most remote regions of our planet. It is imperative that such critical scientific measurements continue, and that the best-available scientific information is used to inform policy decisions on climate change and many other significant societal issues.

Dr. Benjamin Santer, an atmospheric scientist and one of the organizers of the Statement, took this photo in March 2018.